1. Technical Field
The present invention relates in general to a system and method for blending data sampling techniques. More particularly, the present invention relates to a system and method for blending quadrilateral data values with triangular data values to generate an image.
2. Description of the Related Art
The increase of computer system processing speeds has allowed today's computer systems to perform fairly accurate terrain rendering. In the computer gaming industry, for example, three dimensional terrain rendering is an essential, element for providing a “visual reality” to computer games. In addition to the gaming industry, three-dimensional terrain rendering is utilized in other fields, such as flight simulation and environmental planning.
Software developers may use “ray casting” for terrain rendering, which produces realistic images. However, ray casting algorithms are inherently complex, and, therefore, require excessive processing time. As an alternative, software developers may use vertical ray coherence for terrain rendering. Vertical ray coherence is an algorithm that exploits the geometric fact that if a plane containing two rays is vertical to a plane of a height map, the two rays may be processed using the same small subset of data from a digital terrain model.
While performing vertical ray coherence, a computer system uses vertical half planes to identify vertical rays, such as height map vertical rays, and computes image values along the height map vertical ray. The computer system typically performs either a quadrilateral or triangular calculation during image generation. A challenge found, however, is that conditions exist that one calculation may have an advantage over the other calculation, depending upon the angle of a particular height map vertical ray, to generate a quality image.
What is needed, therefore, is a system and method to combine the advantages of quadrilateral calculations with the advantages of triangular calculations in order to render a quality image.